Merge with 0.2

Apart from resolving merge conflict, the
CompoundMapperTC:test_object_relation test had to be almost entirely
rewritten because tests' schema changed in "default" branch ("author"
relation semantics changed in cdff71d0dd27, we thus now use "in_library"
instead) and because the rendering of array items is now different
(items are objects with a "id" property instead of plain strings
previously).